//用ES5声明一个类,本质是一个函数
function Student() {
    //在Student类下面
    this.say = function(){
        console.log('我在说话')
    }
    this.name = '张三'
}
Student.prototype.walk = function(){
    console.log('我能走路')
}
let stu = new Student('lisi')
stu.name = 'lisi'
console.log(Student, stu.name) //'lisi'